SQL Server not working after upgrading windows8.1 to windows 10

Question

 TITLE: Connect to Server
------------------------------

Cannot connect to Thejus-PC.

------------------------------ ADDITIONAL INFORMATION:

A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or
> was not accessible. Verify that the instance name is correct and that
> SQL Server is configured to allow remote connections. (provider: Named
> Pipes Provider, error: 40 - Could not open a connection to SQL Server)
> (.Net SqlClient Data Provider)
> 
> ------------------------------ For help, click: http://go.microsoft.com/fwlink?ProdName=Microsoft%20SQL%20Server&EvtSrc=MSSQLServer&EvtID=2&LinkId=20476
> 
> ------------------------------ Error Number: 2 Severity: 20 State: 0
> 
> 
> ------------------------------ Program Location:
> 
>    at System.Data.SqlClient.SqlInternalConnection.OnError(SqlException
> exception, Boolean breakConnection, Action`1 wrapCloseInAction)    at
> System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject
> stateObj, Boolean callerHasConnectionLock, Boolean asyncClose)    at
> System.Data.SqlClient.TdsParser.Connect(ServerInfo serverInfo,
> SqlInternalConnectionTds connHandler, Boolean ignoreSniOpenTimeout,
> Int64 timerExpire, Boolean encrypt, Boolean trustServerCert, Boolean
> integratedSecurity, Boolean withFailover, SqlAuthenticationMethod
> authType)    at
> System.Data.SqlClient.SqlInternalConnectionTds.AttemptOneLogin(ServerInfo
> serverInfo, String newPassword, SecureString newSecurePassword,
> Boolean ignoreSniOpenTimeout, TimeoutTimer timeout, Boolean
> withFailover)    at
> System.Data.SqlClient.SqlInternalConnectionTds.LoginNoFailover(ServerInfo
> serverInfo, String newPassword, SecureString newSecurePassword,
> Boolean redirectedUserInstance, SqlConnectionString connectionOptions,
> SqlCredential credential, TimeoutTimer timeout)    at
> System.Data.SqlClient.SqlInternalConnectionTds.OpenLoginEnlist(TimeoutTimer
> timeout, SqlConnectionString connectionOptions, SqlCredential
> credential, String newPassword, SecureString newSecurePassword,
> Boolean redirectedUserInstance)    at
> System.Data.SqlClient.SqlInternalConnectionTds..ctor(DbConnectionPoolIdentity
> identity, SqlConnectionString connectionOptions, SqlCredential
> credential, Object providerInfo, String newPassword, SecureString
> newSecurePassword, Boolean redirectedUserInstance, SqlConnectionString
> userConnectionOptions, SessionData reconnectSessionData,
> DbConnectionPool pool, String accessToken)    at
> System.Data.SqlClient.SqlConnectionFactory.CreateConnection(DbConnectionOptions
> options, DbConnectionPoolKey poolKey, Object poolGroupProviderInfo,
> DbConnectionPool pool, DbConnection owningConnection,
> DbConnectionOptions userOptions)    at
> System.Data.ProviderBase.DbConnectionFactory.CreateNonPooledConnection(DbConnection
> owningConnection, DbConnectionPoolGroup poolGroup, DbConnectionOptions
> userOptions)    at
> System.Data.ProviderBase.DbConnectionFactory.TryGetConnection(DbConnection
> owningConnection, TaskCompletionSource`1 retry, DbConnectionOptions
> userOptions, DbConnectionInternal oldConnection, DbConnectionInternal&
> connection)    at
> System.Data.ProviderBase.DbConnectionInternal.TryOpenConnectionInternal(DbConnection
> outerConnection, DbConnectionFactory connectionFactory,
> TaskCompletionSource`1 retry, DbConnectionOptions userOptions)    at
> System.Data.ProviderBase.DbConnectionClosed.TryOpenConnection(DbConnection
> outerConnection, DbConnectionFactory connectionFactory,
> TaskCompletionSource`1 retry, DbConnectionOptions userOptions)    at
> System.Data.SqlClient.SqlConnection.TryOpenInner(TaskCompletionSource`1
> retry)    at
> System.Data.SqlClient.SqlConnection.TryOpen(TaskCompletionSource`1
> retry)    at System.Data.SqlClient.SqlConnection.Open()    at
> Microsoft.SqlServer.Management.SqlStudio.Explorer.ObjectExplorerService.ValidateConnection(UIConnectionInfo
> ci, IServerType server)    at
> Microsoft.SqlServer.Management.UI.ConnectionDlg.Connector.ConnectionThreadUser()
> 
> ===================================
> 
> The system cannot find the file specified

Answer 1

Please verify that Service "SQL Server (MSSQLSERVER)" is started.

I started the "SQL Server (MSSQLSERVER)" service and now i am able get into Sql server.

Answer 2

Please verify that Service "SQL Server (MSSQLSERVER)" is started. Just now I upgraded to Windows 10 and got the same issue.

I started the "SQL Server (MSSQLSERVER)" service and now I am able get into Sql server.